Motor driven wheel chair



Dec. l0, 1940. P, SMITH 2,224,411

MOTOR DRIVEN WHEEL CHAIR Filed-oct. 17, '193s 2 sheets-sheet 1 BY Y r 2 'AHORNEY I Dec. 10, 1940. H. P. SMITH 2,224,411

MoToR DRIvEN WHEEL CHAIR Filed Oct. 17, .19,38 2 Sheets-Sheet 2 1N VEN TOR.

Patented Dec. 10,' 1940 UNITED STATES Moron 'DRTVEN WHEEL cnam Homer E. Smith, Seattle, Wash. Application October 17, 193s, serial No. 235,437

4 Claims.

This invention relates to motor driven wheel chairs and an Object of this invention isto pro-` vide a motor driven wheel chair that can be moved forwardly or rearwardly at will and that 5 can be turned in either direction either on the vertical axis of the chair or on the vertical axis of either of the wheels and that can be moved in substantially any manner desirable to the Occupant.

Another object of the invention is toprovide efficient control means for an electrically driven wheel chair whereby the occupant can control all of the movements of the chair by a simple process of closing electric switches.

Another Object is to providecontrol meansof this nature that is particularly well adapted to be operated by invalids, said control means comprising switches that are easily operated but that must be held closed by conscious effort on'V the part of the operator and that will move to open position in case the operator loses consciousness.

Another object of the invention is to provide a wheel chair which is compact in construction and relatively short in over all length whereby it may be turned in a small space.

Another object is to provide a motor driven wheel chair having four independently controlled driving shafts, two of which are connected with each wheel of the chair for selectively driving either of said wheels orboth of said Wheels in either desired direction whereby saidchair. may be moved forward or backward Or may bevturned in either direction either on the verticala'xis of the chair or on the vertical axis of one'v of the wheels. y i

Another Objectis to provide a motor driven wheel chair comprising two spaced apartwheels having a frame supported by said wheels .and positioned between vsaid wheelsl below the' axis 40 of said wheels and having a chair positioned between the wheels and supported from the frame, said frame having small caster wheelsjat the front and rear portion thereof to engage with the floor on which the chair rests and prevent tipping. y

Other and more specic objects of the'invention will be apparent from the following description taken in connection with the accompanying drawings.

In the drawings Fig. l is a view partly inside elevation and partly in vertical section of a motor driven wheel chair constructed in accordance with this invention.

Fig. 2 is a View partly in plan and partly in horizontal section substantially on broken line 2-.-2 of Fig. 1, of my motor driven wheel chair.

Fig. 3 is a fragmentary plan View of a portion of a chair arm showing electric switch mechanism connected therewith. p Fig. 4 is ay wiring diagram showing diagrammatically the electrical devices and connections therefor.

Fig. 5 is :a fragmentary plan View showing a modified form of driving means.

Like reference numerals designate like parts throughout the several views.

In the drawings, I0 designates ay frame capable v of supporting the electric driving means required for operating the chair. Preferably this frame It consists of a platform having transverse members l I, on the top side thereof and having cover means I2 on the transverse members Il. Two wheel supporting brackets I3 are secured to the frame I Il near opposite sides thereof and extend upwardly therefrom. Two wheels I4 are journaled on the wheel supporting brackets I3.

Two chair supports I5 0f inverted U shape` extend upwardly from the frame 5, adjacent the sides thereof and a chair I3 is adjustably mounted on the chair supports I5 by bracket means I'I. A screw I8 in the bracket means I'I may be loosened to permit adjustment of the chair on the chair supports I5 and tightened to holdthe bracket means I'I immovable on the chair supports I5. Two drive shaft assemblies designated generally by I9 and 2D in Figs. 1 and 2, are providedon 'the frame I0 and extend crosswise of said frame in front of and to the rear of the wheels I4 respectively. 'I'hese two drive shaft assemblies are vof duplicate construction and the following description and numerals apply equally well to either one. Each drive shaft assembly comprises a tubular shaft or quill 2| journaled in bearings 22 that are secured to the frame Ill. Two clutch members 23 on the respective ends of the tubular shaft 2l, engage with the bearings 22 and prevent endwise movement of the tubular shaft 2i Two drive shafts 24 and 25 are telescopically and rotatably disposed within the tubular shaft 2l and project outwardly from the ends thereof. A bearing member 26 is provided for each drive shaft.z A collar 2'I is secured to each drive shaft 24 and 25 adjacent the bearing member 26 to prevent outward movement of the shaft. A clutch member 28 is provided on each shaft 24 and 25' between the collar 21 and the clutch member 23' on the adjacent end of the tubular shaft 2l. Each pair of clutch members 23 and 28 have complementary teeth 29 and grooves 30 adapted to intert in the manner common to clutches. Each clutch member 28 is connected with its shaft by a spline or key member 3| so that the clutch member 28 and its shaft must rotate together but the clutch member is left free to move longitudinally of the shaft. A gear pinion 32 on the outer end portion of each shaft meshes with a gearwheel 33 on the adjacent wheel I4. A sprocket wheel 34 is secured to each tubular shaft 2| and link belts 35 andI 36 connect the respective sprocket wheels 34 with two sprocket wheels 31 and 38 of a speed reduction gear 39. 'The two sprocket wheels 31 and 38 rotate in opposite directions so as to drive the two tubular shafts 2| in opposite directions. An electric motor 40 is connected by belt means 4| with the speed reduction gear 39 for driving the same.

Each clutch member 28 has a shifter arm 42 connected therewith. Each shifter arm 42 is fulcrumed on a pivot 43 and has a spring 44 connected with it in such a manner as to urge the clutch 28 into a disengaged position. Preferably a stop member 45 is' provided for limiting the movement of the clutch arm in one direction. Four electromagnets 46, 41, 48 and 49 are provided for operating the four clutches. These electromagnets are shown in plan in Fig. 2, and are shown diagrammatically in Fig. 4. E'ach electromagnet is positioned so as to exert a pull on an armature 45' on the adjacent lever 42.

A caster wheel 9 is provided at each corner of the frame to stabilize and balance the chair and to provide for easy turning of said chair in all directions. The caster wheels are positioned so that they are slightly above the floor when the frame I9 is parallel with the floor. This allows for a slight tilting movement of the frame, prevents more than one pair of said caster Wheels from contacting the floor at one time, facilitates going over door sills, rugs, and like obstructions and insures that the major 'portion of the weight of the chair will always be carried by the main wheels I4.

Preferably the motor 46 is a direct current motor and is electrically connected in series with two six volt batteries 50 and 5|, as diagrammatically shown in Fig. 4. In said Fig. 4, the two batteries 56 and 5| are connected with each other by a conductor 52 and said batteries are connected with the motor 48 by conductor 53, conductor 54, relay operated switch 55 and conductors 56 and 51. The relay 58 that operates switch 55 is connected by conductors 59 and 51 with one side of one of the batteries, such as the battery 5I, and by conductor 60, switch 6| and conductors 62, 63 and 52 with the other side of the battery 5|. This provides for energizing the relay 58 with six volt current when the switch 6| is closed. Four switches 64, 65, 66 and 61 control the ow of current to the respective electromagnets 46, 41, 48 and 49 by which the clutch members 28 are operated. Preferably the electromagnets are adapted to be energized with six volt current. To this end the two electromagnets 46 and 48 on one side of the chair are preferably connected with one battery, such as the battery 5I and the two electromagnets 41, and 49 on the other side of the chair are connected with the other battery 5D. This approximately equalizes the load on the two batteries. The electromagnet 46 is connected by conductors 68, 62, 63 and 52 with one side of battery 5| and by conductor 69, switch 64 and conductors 10 and 51 with the other side of battery 5|. The electromagnet 48 is connected by conductor 1| with one side of battery 5| and by conductor 12, switch 66 and conductors 13 and 51 with the other side of battery 5|. The electromagnet 41 is connected by conductors 14 and 53 with one side of the battery 58 and by conductor 15, switch 65, and conductors 16 and 63 with the other side of the battery 50. The electromagnet 49 is connected by conductors 11 and 53 with one side of the battery 58 and by conductor 18, switch 61 and conductors 19, 16 and 63 with the other side of the battery 50. Obviously, with the connections just described, the switches 64, 65, 66 and 61 control the electro- `magnets 46, 41, 48 and 49 respectively. The

switch 6| controls the relay 58 which in turn controls the circuit to the motor 49.

Preferably the switches 6|, 64, 65, 66 and 61 are positioned in or on an arm 86 of the chair, as shown in Figs. 1 and 3 so that they are easily accessible to the operator. These switches are preferably of the push button type as shown. A flat plate 8| is preferably connected by pivot means 82 with the chair arm 89 and positioned to engage the switch 6| and form a comfortable rest upon which the wrist of the operator may be placed when the switch is to be operated. A spring 83 urges the switch 6| into open switch position and said spring is preferably strong enough so that the weight of the hand and forearm of the operator will not close the switch 6| unless a conscious effort is made to close said switch 6I by exerting a downward pressure on the plate 8l. If the ,switch 6| should be closed accidentally it will start the motor 40 but this will not move the chair unless one or more of the switches 64, 65, 66 and 61 are closed at the same time as the switch 6 I.

Means is provided to prevent the two switches 64 and 66 from being closed at the same time and to prevent the two switches 65 and 61 from being closed at the same time. The means for accomplishing this purpose shown in Figs. 1 and 3 consists of a lever plate 84 overlapping each pair of switch buttons 64-66 and 65-61 and pivoted between the two switch buttons for rocking movement. When one end of a lever plate is pressed inwardly the opposite end thereof will move outwardly and prevent pressure on the other switch button of the pair. Other means of well known form may be provided for preventing the closing of one switch when the other switch of the pair is closed. Obviously the switch means may be separate from the arm of the chair and may be positioned for operation by the feet or by any other part of the body, depending on the physical condition of the patient using the chair.

In the operation of this device, whenever the switch 6I is closed the motor 40 will be operated but the chair will not be moved unless one or more of the other switches 64, 65, 66 or 61 is closed at the same time. If the operator desires to move forward he will close switches 6| 66 and 61. This will operate motor 4|] to drive the tubular shafts 2| and at the same time energize electromagnets 48 and 49 to engage the two clutches on the forward shaft assembly and drive the wheels I4 in the proper direction to move the chair forward. By simultaneously closing switches 6|, 64, and 66 the electromagnets 46 and 41 will be energized and the clutches of the rear shaft assembly engaged to drive the wheels in the proper direction to move the chair rearwardly. If the switch 6I and any one of the switches 64, 55, 66 or 61 are simultaneously closed one wheel I4 will be driven and the opposite wheel I4 will stand still and the chair will be turned on the vertical axis of the non-driven wheel. If the switch 6I and two diagonally opposite switches, such as the two switches 64 and 51 or the two switches 6B and 65 are simultaneously closed then one wheel I4 will be rotated in one direction and the other wheel will be rotated in the opposite direction and the chair will be turned substantially on its own vertical axis and in the least space in which it is possible to turn said chair. This gives to yany operator that is ableto operate the switches complete control of the chair and makes it possible for them to maneuver the chair in the least possible space.

In Fig. 5, I have shown a modified form of drive means comprising a sprocket wheel 81 on each drive shaft 24 and 25 connected by a link belt 88 with a sprocket wheel 89 that is secured to the adjacent wheel I4. 'Ihis provides two link belt driving connections to each wheel I4.

The foregoing description and accompanying drawings clearly disclose a preferred embodiment of my invention but it will be understood that this disclosure is merely illustrative and that changes may be made within the scope and spirit of the following claims.

I claim:

1. A motor driven wheel chair comprising two spaced apart wheels, a frame supported by said wheels and positioned between'said wheels below the axes of said wheels; a chair supported from said frame and positioned between said wheels; two drive shafts positioned in front of said wheels; two other drive shafts positioned to the rear of said wheels; a driving connection between each drive shaft and a wheel; driving means for said drive shafts; and an independent control for selectively connecting each drive shaft with said driving means, whereby either of said wheels may be driven in either desired direction.

2. A motor driven wheel chair comprising two spaced apart wheels, a frame supported by said wheels and positioned between said wheels below the axes of said wheels; a chair supported from said frame and positioned between said wheels; two driven members positioned transversely of 3. A motor driven wheel chair comprising two spaced apart wheels, a frame supported by said wheels and positioned between said wheels below the axes of said wheels; a chair supported from said frame and positioned between said wheels; two driven members positioned transversely of said frame adjacent the front and rear portions of said wheels respectively; two shafts aligned with each driven member and extending in opposite directions therefrom; clutch means releasably connecting each shaft with one of said driven members; a driving connection between each shaft and an adjacent wheel; driving means connected with said driven members; an electromagnet controlling the operation of each clutch; and switch means operable by the occupant of the chair for selectively energizing any of said electromagnets to thereby engage any desired clutch.

4. A motor driven wheel chair comprising two spaced apart wheels, a frame supported by said wheels and positioned between said wheels below the axes of said wheels; a chair supported from said frame and positioned between said wheels; two rotatably mounted tubular shafts positioned transversely of said frame adjacent the front and rear portions of said wheels; two driving shafts rotatable within eachv tubular shaft and extending outwardly from the respective ends of the tubular shaft; a clutch for selectively connecting or disconnecting each driving shaft relative to its respective tubular shaft; an electromagnet operatively connected with each clutch; switch means operable by the occupant of the chair for selectively energizing any of said electromagnets; means for driving each of said tubular shafts; and driving means connecting each driving shaft with the wheel adjacent thereto.

HOMER P. SMITH. 

